CCNA Routing Protocols & Concepts. Chapter 11 OSPF
B(config-router)# network 192.168.1.0 0.0.0.3 area 0
B(config-router)# network 10.16.1.0 0.0.0.224 area 0
B(config-router)# network 10.16.1.0 255.255.255.224 area 0
B(config-router)# network 192.168.1.0 255.255.255.255 area 0
B(config-router)# network 10.0.0.0 255.255.255.255 area 0
An external type 2 OSPF route.
An external OSPF route at least two hops away.
An external OSPF route from two different sources.
An external OSPF route that will not increment in cost.
The route was distributed into OSPF from a type 2 router.
Root router
Backup root router
Domain router
Designated router
Backup designated router
2
110
1786
1.544
254
Bandwidth
Bandwidth and hop count
Bandwidth and reliability
Bandwidth, load, and reliability
Area id
K-values
Metric value
Hello interval
Network type
Router C cannot win a DR election under any circumstances.
If the link for interface 192.168.1.4 goes down, router B will become the new DR.
The highest router ID was most likely determined via an OSPF router-id statement or statements.
If a new router is added with a higher router ID than router D, it will become the DR.
All routes for the entire network will be present.
Routes for connected networks that are operational will be in the routing table.
Because the SPF algorithm has not completed all calculations, no routes will be in the table.
A summary route for all previously learned routes will automatically appear in the routing table until all LSPs have been received by the router.
The number 2 is the autonomous system number.
The number 2 indicates the number of networks advertised by OSPF.
The number 2 identifies this particular instance of OSPF on this router.
The number 2 indicates the priority of the OSPF process on this router.
B(config)# int fa0/0 B(config-if)# router-id 192.168.1.5
B(config)# int lo0 B(config-if)# ip address 192.168.1.5
B(config)# router ospf 1 B(config-router)# router-id 192.168.1.5
B (config)# router ospf 1 B(config-router)# ip address 192.168.1.5
4
5
6
7
10
90
100
110
115
120
A FULL adjacency is formed.
A 2WAY adjacency is formed.
Router2 will become the DR and Router1 will become the BDR.
Both routers will become DROTHERS.
2
156
1564
1785
1787
A will become the DR. D will become the BDR
A will become the DR. C will remain the BDR.
D will remain the DR. A will become the BDR.
D will remain the DR. C will remain the BDR.
192.168.0.0/24 through 192.168.0.15/24
192.168.0.0/24 through 192.168.15.0/24
192.168.15.0/24 through 192.168.31.0/24
192.168.15.0/24 through 192.168.255.0/24
192.168.16.0/24 through 192.168.255.0/24
Shut down the loop back interface
Use the OSPF router-id 192.168.100.1 command
Use the clear ip ospf process command
Nothing, the router-id of Router1 is already 192.168.100.1
DR for network 192.168.1.200
BDR for network 192.168.1.200
DROTHER on 192.168.1.200
DR for network 192.168.1.204
BDR for network 192.168.1.204
Any traffic through the router interfaces
Routing database updates
Hello packets
BPDU packets
Elections are always optional.
Elections are required in all WAN networks.
Elections are required in point-to-point networks.
Elections are required in broadcast multiaccess networks.
Elections are required in non-broadcast multiaccess networks.
RouterB(config)# router ospf 10 RouterB(config-router)# gateway-of-last-resort 172.16.6.6 RouterB(config)# ip route 0.0.0.0 0.0.0.0 serial 0/0/0
RouterB(config)# ip route 0.0.0.0 0.0.0.0 172.16.6.6 RouterB(config)# router ospf 10 RouterB(config-router)# default-information originate
RouterB(config)# router ospf 10 RouterB(config-router)# default-network 172.16.6.6 0.0.0.3 area 0 RouterB(config)# ip route 0.0.0.0 0.0.0.0 172.16.6.6
RouterB(config)# ip default-route 0.0.0.0 0.0.0.0 172.16.6.6 RouterB(config)# router ospf 10 RouterB(config-router)# redistribute ip default-route
RouterB takes over as DR and RouterD becomes the BDR.
RouterD becomes the BDR and RouterA remains the DR.
RouterD becomes the DR and RouterA becomes the BDR.
RouterC acts as the DR until the election process is complete.
There is no change in the DR or BDR until either current DR or BDR goes down.
HQ will be DR for 10.4.0.0/16.
Router A will be DR for 10.4.0.0/16.
HQ will be BDR for 10.4.0.0/16.
Remote will be DR for 10.5.0.0/16.
Remote will be BDR for 10.5.0.0/16.
OSPF autonomous system IDs do not match.
OSPF process IDs do not match.
OSPF network types are identical.
OSPF hello or dead timers do not match.
R1(config-router)# network 10.0.0.0 0.0.0.0 area 0
R1(config-router)# network 0.0.0.0 255.255.255.255 area 0
R1(config-router)# network 10.1.0.0 0.0.0.255 area 0
R1(config-router)# network 172.16.1.0 0.0.0.3 area 0
R1(config-router)# network 172.16.0.0 0.255.255.255 area 0
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